The U.S. Environmental Protection Agency will tighten ozone pollution standards this week. That's a victory for people with breathing problems and heart disease.

But it's not as big a victory as it should be. The new standards will be only a modest improvement. That's because the Bush administration is poised to ignore the recommendations of an independent scientific advisory committee and set the new standard above where it should be.

The administration is under court order to tighten the standard, but the judge didn't say where the level should be set. That's up to the EPA.

The current ozone standard is 0.08 parts per million. The scientific advisory group unanimously endorsed a new standard of between 0.06 and 0.07 parts per million. The administration's new standard is expected to be 0.075 parts per million, a level that the committee said is too high to protect public health. Each year, thousands of Americans die prematurely from exposure to what scientists call ground-level ozone. A 2004 study published in the Journal of the American Medical Association found that even short-term increases in ozone levels result in higher premature death rates, especially among infants, the elderly and people with heart or lung problems. The deaths occur even when ozone levels are at or below the current EPA standard, researchers concluded.

Ground level ozone is a key component in smog, which forms when sunlight cooks certain common pollutants. Industry groups have vigorously opposed a new ozone standard because it would trigger the need to reduce emissions of nitrogen oxides and other smog-forming chemicals from factory smokestacks and vehicle tailpipes.

Among the cities that would be affected is St. Louis. The metropolitan region traditionally has difficulty meeting ozone standards, especially during the warm summer months.

Last year, lawmakers in Missouri and Illinois exempted older cars, those most likely to spew smog-forming chemicals, from emissions testing programs. That's going to make meeting the new standard even more difficult.

Failing to do so could trigger a host of new restrictions that could limit development or expansion of existing businesses or force the loss of some federal highway aid.

Worse, failure to meet the standard also means that many people with lung and heart problems will die prematurely; many more will suffer disabling illnesses.

One way or another, the costs of ozone pollution must be paid. The best public policy is to target those responsible for releasing ozone-forming chemicals into the air.

The worst is to do nothing and force the vulnerable - infants, the elderly and disabled - to pay with their health and their lives.